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protoplasm, just as tlie properties of water are the resultant of 
the combined properties of its constituent hydrogen and oxygen; 
and it is alleged to be just as absurd to set down the pheno- 
mena of life to an assumed “vital force,” as it would be to 
ascribe the properties of water to an assumed “aquosity.” 
Now it appears to me, that in considering such an assertion, 
there are two important points to bear in mind. In the first 
place, it seems clear that in speaking of life as a “ property” 
of protoplasm, we are really using a phrase which might admit 
of more than one interpretation. Wliat in the case of a lifeless 
body are understood as its “properties,” are either certain in- 
herent qualities (as learned by our sensations), or else they are 
certain reactions, which are of constant and invariable occur- 
rence whenever the body in question is acted upon in a parti- 
cular manner. From the point of view here taken, however, 
life consists of actions as well as of reactions, and to speak of 
the former as being “properties” of protoplasm is simply to 
beg the entire question at issue; while it may be presumed that 
even the most ardent advocates of the physical theory of life 
would not be prepared to assert that life is an inherent quality 
of protoplasm. 
In the second place, the assertion that life is merely a “ pro- 
perty” of protoplasm, is one which ignores the difference be- 
tween dead protoplasm and living protoplasm. Even as regards 
the phenomena of irritability and contractility — as manifested 
in the protrusion of pseudopodia by all naked masses of living 
protoplasm — it is certain that we have to deal with something 
which cannot be justly spoken of as a property of protoplasm. 
On the contrary, the manifestations of irritability are in the 
most obvious manner directly dependent upon the fact that the 
protoplasm is in that peculiar condition to which we apply the 
tevm“ living Irritability and contractility are not inherent pro- 
perties of protoplasm qua protoplasm ; and those who make such 
an assertion must be taken as maintaining the thesis that proto- 
plasm has no existence in its dead state, and that we are only 
acquainted with it in its living condition. Considering, how- 
ever, that the greater part of our entire knowledge of proto- 
plasm, as an actual substance, is based upon the observation 
and examination of dead protoplasm, that we are still ignorant 
of its composition as a definite chemical compound, and that 
there is not a particle of scientific evidence to show that the 
protoplasm of a dead animal is in any way physically or chemi- 
cally different from that of the same animal when alive, until, 
at any rate, decomposition has occurred — considering these 
things, we may well maintain that the assertion that life is a 
